Alpha-1-Antitrypsin (AAT) is a protein of the SERPINA1 gene. A single amino acid mutation (Lys342Glu) results in an expression of misfolded Z-AAT protein, which has a high propensity to intra- and... Show moreAlpha-1-Antitrypsin (AAT) is a protein of the SERPINA1 gene. A single amino acid mutation (Lys342Glu) results in an expression of misfolded Z-AAT protein, which has a high propensity to intra- and extra-cellular polymerization. Here, we asked whether levels of circulating Z-AAT polymers are associated with the severity of lung disease, liver disease, or both. We obtained cross sectional data from the Dutch part of the Alpha1 International Registry of 52 ZZ-AAT patients who performed a pulmonary function test and donated a blood sample on the same day. From the Alpha-1 Liver Aachen Registry, we obtained a cohort of 40 ZZ-AAT patients with available data on their liver function. The levels of plasma Z-AAT polymers were determined using a LG96 monoclonal antibody-based sandwich ELISA. In a Dutch cohort, the median plasma level of Z-AAT polymers of patients diagnosed for pulmonary disease was 947.5 mu g/mL (733.6-1218 mu g/mL (95% CI)), which did not correlate with airflow obstruction or gas transfer value. In the Alpha-1 liver patient cohort, the median polymer level was 1245.9 mu g/mL (753-2034 mu g/mL (95% CI)), which correlated with plasma gamma-glutamyl transferase (GGT, rs = 0.57, p = 0.001), glutamate dehydrogenase (GLDH, rs = 0.48, p = 0.002) and triglycerides (TG, rs = 0.48, p = 0.0046). A Wilcoxon rank test showed higher Z-AAT polymer values for the liver over the lung group (p < 0.0001). These correlations support a possible link between plasma Z-AAT polymers and the liver function. Show less
Noone, D.P.; Velden, T.T. van der; Sharp, T.H. 2021
The pentraxin family of proteins includes C-reactive protein (CRP), a canonical marker for the acute phase inflammatory response. As compared to normal physiological conditions in human serum,... Show moreThe pentraxin family of proteins includes C-reactive protein (CRP), a canonical marker for the acute phase inflammatory response. As compared to normal physiological conditions in human serum, under conditions associated with damage and inflammation, such as acidosis and the oxidative burst, CRP exhibits modulated biochemical properties that may have a structural basis. Here, we explore how pH and ligand binding affect the structure and biochemical properties of CRP. Cryo-electron microscopy was used to solve structures of CRP at pH 7.5 or pH 5 and in the presence or absence of the ligand phosphocholine (PCh), which yielded 7 new high-resolution structures of CRP, including pentameric and decameric complexes. Structures previously derived from crystallography were imperfect pentagons, as shown by the variable angles between each subunit, whereas pentameric CRP derived from cryoEM was found to have C5 symmetry, with subunits forming a regular pentagon with equal angles. This discrepancy indicates flexibility at the interfaces of monomers that may relate to activation of the complement system by the C1 complex. CRP also appears to readily decamerise in solution into dimers of pentamers, which obscures the postulated binding sites for C1. Subtle structural rearrangements were observed between the conditions tested, including a putative change in histidine protonation that may prime the disulphide bridges for reduction and enhanced ability to activate the immune system. Enzyme-linked immunosorbent assays showed that CRP had markedly increased association to the C1 complex and immunoglobulins under conditions associated with acidosis, whilst a reduction in the Ca2+ concentration lowered this pH-sensitivity for C1q, but not immunoglobulins, suggesting different modes of binding. These data suggest a model whereby a change in the ionic nature of CRP and immunological proteins can make it more adhesive to potential ligands without large structural rearrangements. Show less
Westdijk, J.; Metz, B.; Spruit, N.; Tilstra, W.; Gun, J. van der; Hendriksen, C.; Kersten, G.F.A. 2017
This thesis focuses on describing novel methodology for studying the complement system in experimental rodent models, on fundamental aspects of mouse complement, and the activation and... Show moreThis thesis focuses on describing novel methodology for studying the complement system in experimental rodent models, on fundamental aspects of mouse complement, and the activation and contribution of complement system in experimental renal ischemia/reperfusion (I/RI) and renal autoimmune disease animal models. Our findings show that transient and acute complement activation is observed following renal I/RI and that the developed and validated methodology for analysis of systemic complement can be a valuable addition to complement analysis in preclinical studies. Our novel findings included the characterisation of C5a receptor C5L2 and its contribution to renal I/RI. Our results revealed injurous contribution to the pathology of renal I/RI, in similar degree as with C5aR. Using anti-GBM renal autoimmune disease as an experimental model, we showed for the first time in vivo that properdin, the only positive regulator of complement, may direct complement activation independent of classical ligands such as C3. Other findings included the characterisation of drastic gender difference in mouse complement, where female mice have near-deficient terminal pathway serum activity, and the impact of therapeutic dietary restriction on serum complement, which was shown to downregulate the hepatic expression of the terminal pathway components in serum. Show less
Langers, A.M.J.; Verspaget, H.W.; Hawinkels, L.J.A.C.; Kubben, F.J.G.M.; Duijn, W. van; Reijden, J.J. van der; ... ; Sier, C.F.M. 2012
A vaccine against Plasmodium falciparum is needed to augment currently available malaria control tools. A handful of parasite antigens are at various stages of pre-clinical and clinical development... Show moreA vaccine against Plasmodium falciparum is needed to augment currently available malaria control tools. A handful of parasite antigens are at various stages of pre-clinical and clinical development. Amongst these is P. falciparum apical membrane antigen 1 (PfAMA1), an antigen expressed by asexual stage parasites and believed to be important for the parasite__s invasion of both red blood cells and liver cells. The immune response to PfAMA1 is mediated mainly by antibodies that prevent parasite invasion of host cells. PfAMA1 however shows allelic polymorphism, with anti-PfAMA1 antibody responses exhibiting strain-specificity. This thesis investigated multi-allele vaccine formulation strategies that would overcome the strain-specificity of antibody responses to PfAMA1. The main findings of this thesis are that i) different PfAMA1 alleles share epitopes to which functional cross-strain antibodies can be induced, ii) a three-allele PfAMA1 formulation yields the greatest proportion of functional cross-strain antibodies, and iii) three PfAMA1 alleles, irrespective of the adjuvant used for formulation and whether they are administrated as a multi-allele formulation or sequentially, induce similar proportions of cross-strain antibodies. Overall, a multi-allele formulation with three in silico-designed PfAMA1 candidates yields antibodies that inhibit several parasites in vitro and warrant their development as a human blood stage vaccine. Show less
